FAQ Keratoconus/Cross-linking

Below you will find a collection of frequently asked questions and our answers. Besides, you may find useful information on the internet and also various groups on Facebook on the topic, the “Keratoconus Group” being the largest, with more than 10’000 members and counting.
The website of the ELZA Institute provides useful information on the topic and access to a large number of scientific articles, videos, and popular articles on the topic.

What is Keratoconus

Keratoconus is a disease that goes along with a diminished biomechanical stability of the cornea. The cornea becomes too soft, leading to an increased bulging and protrusion of the cornea. Since the cornea represents an important part of the eye’s optics, a number of symptoms occur: fluctuations in visual acuity, a reduction of visual acuity that cannot entirely be corrected for with glasses or even contact lenses, and halos around light sources.

Other symptoms include an increased sensitivity to light and glare. Even the best pair of optical glasses may not achieve good vision. Keratoconus has an incidence of 1:1500 patients in the general population.

The causes are still unknown: an increased incidence in families might indicate genetic causes. Another factor that clearly indicates an increased risk for keratoconus development is extensive eye rubbing over years, for example in chronic allergies.

How common is keratoconus? Who is more likely to have progressive keratoconus?

It is estimated that 1:1500 people have keratoconus. This estimation is an average because the incidence rate depends on geographical region, with higher incidence in the Middle East countries.

Aggressive forms (progressive state) are found in children and adolescents.

The Down Syndrome population is at the highest risk (1:67).

What are symptoms of keratoconus? Am I progressing?

The most common is a loss in visual acuity first with slight blurring and increased sensitivity to light, due to induced irregular astigmatism.

Since the disease can be progressive among children and adolescents, the impairment of vision may also continue to progress. An important indicator is an increase in the amount of astigmatism measured.

If I have keratoconus, should my whole family be screened?

Yes, genetic factors appear to play a role in the development of the disease.

Is Keratoconus related to Down Syndrome?

The incidence of keratoconus in Down Syndrome is 1:67, considerably higher than in the general population. Most of these cases remain undiagnosed.

What is cross-linking ?

Cross-linking is a method to mechanically stabilize the cornea. More information can be found here and here.

Is cross-linking new in medicine?

No. Cross-linking has been in clinical use in other medical disciplines for decades (orthopedic surgery, ear-nose-throat surgery, heart surgery). Using this technology on the eye is relatively new (15 years of experience).

Is CXL for keratoconus approved by the European Community or the FDA?

Currently, the CXL treatment method for keratoconus has been approved for use in the European Community since 2005, and in over 100 countries worldwide.
The FDA approval for the treatment in the US was granted in April 2016.

How does cross-linking work?

Cross-linking induces an increased number of bonds between the collagen fibers of a connective tissue. This can be compared to a net that receives additional links and becomes mechanically more resistant.

What is the "Light for Sight" protocol?

Whereas the technical aspects of corneal cross-linking in children and adolescents are not different from a CXL procedure performed in adults, there are some fundamental differences that need to be respected in young patients up to the age of 20 years:

Is cross-linking (CXL) Safe?

Cross-linking of the cornea is achieved by a combination of UVA irradiation and application of riboflavin eye drops (vitamin B2). The intensity of the irradiation has been carefully adapted to the eye so that no deeper structures can be damaged. This method is in clinical use since 1999 and the team leaders of our reference sites are among the most renowned CXL experts worldwide.

How safe is CXL treatment for children?

Up-to-date evidence indicates that CXL for children has a very high safety profile, similar to CXL in adults.

What is the goal of the surgery?

The goal of the operation is to stabilize keratoconus. The disease cannot be reversed but the current state can be frozen. In a later stage, there is help to restore visual acuity. In children and adolescents, the method of choice are special contact lenses. Later, as young adults, a number of other options will be available, including intrastromal rings and excimer laser treatments. Should you ever need a corneal transplantation at a later moment in time, such procedure may be performed in a cross-linked cornea without problems.

What happens after surgery?

Postoperative pain: A part of the corneal surface will be open at the end of the CXL procedure, comparable to a slow blindness. The open cornea will be painful which is a normal part of the procedure. The pain gradually dissolves and will be completely gone within 48 hours. You should be provided with sufficient pain medication. The doctor’s visit: On the first days following the operation daily controls will be performed. Between day 4 and week 6 after CXL you will apply anti-inflammatory eye drops twice daily (morning and evening).

What are the symptoms that may after the surgery?

Red eye. Your eye will be red during two weeks. This is normal and should not worry you.

Scratching, tearing and burning sensation. May last 6 to 8 weeks. We will prescribe artificial tears that you might use as often as needed.

Blurred vision. Blurred vision may occur during the first 6 to 8 weeks after CXL. At six months after the operation you should achieve the same or even a slightly better visual acuity than before.

Glare and photophobia. Might be distinct in the first postoperative weeks.

Is the CXL treatment covered by health insurance?

CXL is covered by the health insurance in some european countries, but others have not yet implemented this new treatment modality into the official catalogue.